A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
Calories to Rontojoules
Convert Calorie (cal) to Rontojoule (rJ) instantly with an exact formula, conversion table, and FAQ.
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Convert calories (cal) to rontojoules (rJ) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
rJ = cal × 4.184000000e+27
Results update instantly for Calories to Rontojoules conversions.
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Formula
rJ = cal × 4.184000000e+27
cal = rJ × 2.390057361e-28
Conversion table
| 1 cal | 4.184000e+27 rJ |
| 5 cal | 2.092000e+28 rJ |
| 10 cal | 4.184000e+28 rJ |
| 20 cal | 8.368000e+28 rJ |
| 50 cal | 2.092000e+29 rJ |
| 100 cal | 4.184000e+29 rJ |
| 500 cal | 2.092000e+30 rJ |
| 1000 cal | 4.184000e+30 rJ |
Related conversions
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How the formula works
Both calorie and rontojoule measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in calories by 4.184000000e+27 to get rontojoules. To reverse the conversion, multiply a rontojoule value by 2.390057361e-28 to get back to calories.
Frequently asked questions
What is Calorie (cal)?
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C.
What is Rontojoule (rJ)?
A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
How do I convert calories to rontojoules?
Multiply the calorie value by 4.184000000e+27 to get the equivalent in rontojoules. For example, 5 cal × 4.184000000e+27 = 2.092000e+28 rJ.
Is this conversion exact?
Yes. Both units are defined against the SI base unit for this dimension, so the factor 4.184000000e+27 is an exact, non-rounded value.
Can I convert rontojoules back to calories?
Yes. Divide the rontojoule value by 4.184000000e+27, or multiply it by 2.390057361e-28, to get calories.
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About converting calories to rontojoules
A (small) calorie is a thermochemical unit of heat energy equal to 4.184 joules, historically the energy needed to raise 1 gram of water by 1°C. A rontojoule (rJ) is a metric-prefixed unit of energy equal to 10-27 joules, a fraction of a single joule, using the SI ronto prefix.
Use this calculator to move between calories and rontojoules accurately for homework, engineering, billing, or everyday energy calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.